In a wireless communications system such as a mobile cellular communications system, a wireless local area network (WLAN for short), or fixed wireless access (FWA for short), communications nodes such as a base station (BS for short) or an access point (AP for short), a relay station (RS for short), and user equipment (UE for short) are generally capable of transmitting their own signals and receiving signals from other communications nodes. Because a radio signal greatly attenuates on a radio channel, compared with a transmit signal of a receive end, a signal from a communications peer becomes extremely weak when arriving at the receive end. For example, a power difference between a transmit signal and a receive signal of a communications node in the mobile cellular communications system reaches 80 dB to 140 dB or even greater. Therefore, to prevent a receive signal from being blocked or interfered by a transmit signal of a same transceiver, different frequency bands or time periods are used to transmit a radio signal and receive a radio signal, that is, a frequency division duplex (FDD for short) manner or a time division duplex (TDD for short) manner is used.
To improve frequency spectrum efficiency, a full-duplex technology may be used in the prior art. In a wireless full-duplex technology that is different from an existing FDD or TDD technology, transmitting and receiving operations may be simultaneously performed on a same radio channel. In this way, theoretically, frequency spectrum efficiency of the wireless full-duplex technology is two times as much as that of the FDD or TDD technology. A premise for implementing wireless full duplex is that strong interference (referred to as Self-interference) to a receive signal from a transmit signal of a same transceiver is avoided, reduced, and eliminated as much as possible, so that properly receiving a wanted signal is not affected by the strong interference.